In 7th grade I had a teacher that thought it woud be a good idea to show us what happens when you put dry ice in water. Not only did he show is that but he also showed us what happens when the pressure created was contained in a plastic soda bottle. The best thing he did was have student help him. The student put the dry ice in the bottle of water in the class room. The teacher the reacted by caping the bottle. After he relized his mistake he took off running outside. Needless to say he got about half way to setting the bottle down in a safe place and BOOM it went off in his hand. He was not seriously injured just 3 or 4 stiches and he was good as new. We never let him live that one down.